Textile drafting cot



Jan. 27, 1959. J, ROCKOFF 1 2,870389 TEXTILE DRAFTING COT Filed April 20, 1953 INVENTOR. JOSEPH ROCKOFF United States Patent TEXTILE DRAFTING COT Joseph "Rockoif, 'DaytornOh'io, assignor to The Dayton 'Rubber'Company, a corporation of Ohio ApplicatinnApril 20,1953, SerialNo. 349,720

'5 Claims. (Cl. 19-143) The present invention relates to rubber-like compositions'for rollers and the like, particularly textile working units such as roll covers for spinning and drawing rollers. .A textile roller as used in present day drawing, roving :and spinning machines, comprises a metal arbor having'a "thetic fibers. ,In carryingout these.,functions,.such rollers .are subjected to the abrasive action of the fibers and of .other rollers, usuallyofcorrugated steel, with which they are in substantially tangential contact. During their use :On textile machines, these rollers are .also subjected to .undesirable atmospheric conditions, deleterious oils and :thelike present in the fibers, and in addition, :tendto :collect a static .charge. Any one or all of these .last :enurnerated factors may contribute toacondition known :as .eyebrowing which results from the failure of the cots togcarry thevery short fibers or fclearer'waste .to the rearof the clearer inorder to gatherproperly. ,-When gthis condition exists, these short fibers collect at the forward .-edge of the top clearer and hang down over the .roll-to form what is known as an ?eyebrow. 'As the ;size .of the eyebrowfincreases, itwill touchthe yarn ,and. bunches of short gfibers will be pulled into-,the yarn thus impairing its quality with what is knownas a slug. In addition to this condition, there is the additional undesirable phenomenon known as lapping up which re- .sults'when the cot becomes tacky or gummy and presents .an adhesive surface to the fibrous sliver passing between the rollers thereby causing this sliver to'wrap around the cot. It is apparent that when ,this condition exists, the textile working operation is completely disrupted and .much time is consumed in its correction.

While the exact causes of these undesirable'conditions :are-not clearly understood, .it is generally believed that .eyebrowing occurs when the cot becomes smooth surfaced or slick to the extent that it will part with the short clearer waste too readily thereby depositing thisclearer waste at the front of the clearer where .it collectsas an eyebrow rather than carrying it to the rear of theclearer where it builds up without adversely affecting the quality .of the sliver. On the other hand, it is believed that lapping up results when .the atmosphere or oils within the fibers cause the surface of the cots to become sticky and tackythereby overly increasing the tendency of the sliver itself to cling to the cot.

While cots such as those formerly composed of. leather and the like were fairly satisfactory insofar as their tendencies to create eyebrowing and lapping up were concerned, these cots were easily worn by the abrasive action of the cot against the corrugated steel roller with which they were ordinarily in contact, and against the'yarn itself, with the result that these cots became prematurely worn and had to be replaced at considerable expense. On the other hand, textile cots composed of the various 2,870,489 Ratented Jan. 27, 1959 2 types of rubber-like composition could withstand the abrasive wear to which they were subjected butsorne of these compositions had a greater tendency to eyebrow and lap up than did the leather cots.

.It is :an object ofrthe present invention to provide a rubber composition having a surface of controlled roughness and porosity and having suflicient strength for use on rollers such as inking rollers, roll covers such as are used ;;on textile working units, .and .the like.

It is anotherobject of the present invention to provide ,a textile workingunit in the form of a .roll cover which :will be capableofcontinued operation without becoming prematurely worn by abrasion .or'otherwise unusable because of its tendencyrtoeyebrow .or cause lapping up.

It is still anotherobject ofthe present invention to pro- ;vide ,a textile pot ;of synthetic rubber-like composition which, in addition to its ,natural resistance to abrasive wear, Twill notcause lappingwup or-eyebrowing over long ,periodsof use.

.vide .a textile cot, the working ,surface of which has .a ,degree' ofporosity which is easily controlled and may be .maintained at a minimum, consistent with the hardness that. is reguir ed to perform the work of such textile working unit.

Toachieve these other obvious objects and advantages to be apparent from the present disclosure, it is proposed to provide a synthetic rubber-like composit-ionhaving incorporated therein particulate chemically blown sponge rubber materialso arranged that the sponge rubber par ticles will be spaced within the basic matrix composition ofthe cot or roll, particularlynear the working surface thereof so as to impart a controllable degree of roughness and porosity to said surface. It :has been found ,that textile cots formedentirely of sponge rubber materialare generally unsatisfactory with respect to their spinning or :drafting properties, but.theincorporation-of-such material in the form of discrete particles has unexpectedly led to highly satisfactory results.

This provision of sponge rubber particles as a component of a solid rubber cot is also desirable in view of the fact that the sponge rubber particles may ;be formed in the first instance in thin sheets orslabswherein the nature-andextent ofthe blowing and-the porosity resulting therefrom may be more easily controlled and greater uniformity achieved. At the sametime this-provision of the discrete particles of. sponge rubber vvill allow for the necessary porosity and/or roughness upon ,the working surfaceof the 'cots but will, at the same time, allow for sufiicient hardness andrigidity thereoftosatisfactorilyvperform the workfor which thecot is intended. Where, as ,is proposed herein, the sponge rubber particles are formed from a thin sheetoffthe chemically blown sponge rubber composition, the resultingdegree-of porosity .and roughness may be more satisfactorilycpntrolled, not only in the first instance, but also -by con trolling the amount of said particles thatare finally, mixed with the-matrix composition-from whichthc final cot will be molded or extruded. r

It has been found that cots constructedaccording to the above outlined procedure have been capable of operating for considerably longer periods of time without eyebrcaving or lapping up than has heretofore been possible with certain otherrolls of the known types of rubber-like composition.

In the drawings:

Figured is;a perspective of a typical textile rQ-llerin asraese 33 cluding a cot or roll cover according to the present invention.

Figure 2 is a cross-sectional view of the cot of Figure 1 taken on line 22 thereof.

Figure 3 is a perspective of a sheet of chemically blown sponge rubber from which the particles to be used in the present invention may be formed.

Figure 4 is a perspective of such a particle of sponge rubber.

Referring now to Figure 1 there is shown a typical textile roller comprising a metal arbor having raised bosses 11a and 11b formed integrally therewith. About these bosses are aifixed the sleeve-like roll covers or cots 12a.

and 1211 which, in accordance with the present invention, are composed of a base or matrix composition of rubberlike material. Within this matrix composition of the cot are embedded a plurality of discrete particles of sponge rubber such as 1311 and 13b. As best shown in Figure 2, these sponge rubber particles are spaced in a substantially uniform manner throughout the entire matrix composition lZa. The small pores within these particles are shown at 14 and their effect upon the working surface of the cot, wherever these particles come in contact with said surface, is shown at 15.

As previously explained, in order to more perfectly control the degree of porosity resulting from the expansion of the blowing agent incorporated in the manufacture of the chemical sponge, this sponge is preferably made in the form of a thin sheet 16. Such a sheet is conveniently formed by incorporating with a vulcanizable rubber-like composition, a ga evolving blowing agent which, upon subjection of the sheet to vulcanizing conditions such as in a heated platen press, will expand to form the small uniformly spaced pores 17. In order that these pores will be uniformly spaced, it is important that the blowing agent be thoroughly mixed with the rubber-like composition so that it will become evenly distributed therethrough. It has been found desirable to form the sponge rubber sheets to a. thickness of from one-sixteenth to one-eighth of an inch so that this thickness will correspond to one of the dimensions of the particles to be ultimately formed from the sheet.

The sponge rubber composition in sheet form is then preferably frozen, for example by bringing the same in contact with Dry Ice; and, after it is frozen to the point at which it loses its plastic properties, it is subjected to a grinding action. In order that the rubber composition will be maintained in its frozen condition throughout the grinding operation, it is desirable that the contact of the same with the Dry Ice be maintained through the grinding operation, the Dry Ice itself actually passing through the grinder.

From this grinding of the sponge rubber sheet a particle such as 18, having a porous structure, will be formed. Depending upon the degree of porosity desired, the hardness of the matrix composition and other variable factors, the ground particles of sponge rubber may be screened and reground until the desired size is obtained. In typical cot compositions of rubber-like material the preferred size of sponge rubber particle may range from those obtainable by screening through a 6 mesh screen to those obtainable by sifting through a mesh screen.

These particles, when vulcanized and properly screened, may then be admixed with any suitable rubber-like matrix or base composition which will form the bulk of the cot. This mixing may be done on a mill, in a banbury or by other conventional means, and to this extent is treated like any other granular or powdered component such as sulfur which is normally added to rubber-like polymers in the formation of vulcanizable compounds. The matrix composition containing these discrete particles may be molded or extruded into a tubular form, thereafter rag wrapped or otherwise compacted and subjected to vulcanizing conditions. After vulcanization, the tube may,

At of course, be cut into the desired lengths to form the roll covers which will correspond to the length of the boss on the textile roller.

A typical matrix composition to form the base of a textile cot of the present invention may be compounded of the following parts by weight:

Parts by weight The chemically blown sponge rubber composition to be added to the above matrix compound my comprise the following parts by weight:

Parts by weight Butadiene-acrylic nitrile copolymer 100 Plasticizer 10-20 Stearic acid .625 Sulfur 9 Antioxidant 1 Accelerator l Coumarone-indene resin 7.5 Filler (clay) -150 Diazoaminobenzene (blowing agent) 4 It will be observed that in the foregoing examples, the sponge composition is practically the same as the matrix composition except that the sulfur and filler loadings of the former are considerably greater and that a blowing agent is incorporated therewith. The increased amounts of sulfur and filler in the sponge composition are for the purpose of increasing its hardness, so that in the mixing and working of the sponge particles with the matrix composition, they will not become distorted or compressed so as to destroy their porosity. Such hardness is also necessary in the final vulcanization in order that the pressures accompanying the same will not unduly compress or disfigure the particles. The rubber composition from which the sponge particles of the present invention is to be made should in the case of textile spinning and draftcots, preferably be compounded so that if it were vulcanized without blowing, it would have a Shore A durometer hardness of from to just below 100. In addition to compounding for hardness, the strength of the particles may be further increased by so confining the sponge slab that its expansion upon blowing will not cause it to increase in size to more than one and onehalf of its original volume. In general, it is greatly preferred to form the sponge rubber particles of a compound having a greater degree of hardness than that of the matrix compound. For textile spinning and drafting cots the matrix would preferably have a Shore A durometer hardness of about 65 to 85, while the sponge particles are composed of a compound having a Shore A hardness of at least about 85 and up to just below 100. After blowing, of course, the resultant sponge particles would have a lower apparent hardness. For other purposes, as for inking, slashing of fibers, etc., a softer matrix may be desired. In such cases, the sponge compound would also be softer than for cots, but would still be relatively harder than the matrix.

While the basic rubber-like material in the examples above set forth is a butadiene-acrylic nitrile copolymer in each instance, the sponge rubber composition need not he the same as the matrix composition. It has been found, however, that an oil-resistant rubber-like material should be employedin each case. Such materials might include the well-known synthetic oil-resistant compositions such as clLlor-Z-butadiene-LB known as polychloro prene, neoprene, or GRM, and the ethylene dichloride, sodium polysulfide polymers known as Thiokol.

From 50 to 200 parts by weight of the sponge rubber particles may be added based upon the rubber-like polymer in the matrix composition. For the specific composition set forth above, it is found that a suitable top spinning roll cover may be compounded to have 140 parts by weight of the sponge rubber particles passed through an 8 mesh screen to 100 parts by weight of the synthetic rubber-like polymer in the matrix composition. The working surface of this particular cot will have a Shore A durometer hardness ranging from 75 to 85 insofar as the surface is composed of the matrix composition and will have an apparent Shore A durometer hardness of from 62 to 68 in those areas where the sponge rubber particles are exposed to the surface.

The superiority of a textile cot made according to the procedure described herein of compounds according to the above examples has been demonstrated on an experimental drawing frame where such a cot operated for over 60 hours without showing eyebrowing tendencies; while a cot composed only of the matrix compound set forth above and operated on the same drawing frame, ran for only thirty to sixty minutes before it began to show signs of eyebrowing.

While the foregoing description has set forth particular and specific examples, it is to be understood that the embodiments and illustrations employed herein are not to be construed as limitations upon the scope or the principles of this invention as distinctly set forth in the subjoined claims:

I claim:

1. A textile cot for drafting textile fibers having a fiber drafting surface with a degree of roughness and porosity, comprising a matrix of non-porous rubber-like material and a plurality of particles of porous cellular synthetic rubber-like composition embedded therein in substantially uniform spaced relationship, said particles retaining their porosity after incorporation into said surface.

2. A textile cot according to claim 1 wherein said matrix is composed of a butadiene-acrylic nitrile copolymer.

3. A textile cot according to claim 2 wherein said rubber-like composition is a chemically blown sponge having a greater hardness prior to blowing than said matrix.

4. A textile cot according to claim 3 wherein said matrix has a Shore A durometer hardness of about to and said rubber-like composition has a Shore A durometer hardness of between 85 and 100.

5. A textile cot according to claim 1 in which there are 50 to 200 parts of said particles by weight to parts of said matrix by weight.

References Cited in the file of this patent UNITED STATES PATENTS 226,057 Gerner Mar. 30, 1880 2,120,281 Hunt June 14, 1938 2,147,362 Bloomberg Feb. 14, 1939 2,386,583 Bacon Oct. 9, 1945 2,467,213 Luaces Apr. 12, 1949 2,507,869 Rothermel May 16, 1950 

